When producing characters or other representations such a title set by photographic printing, a projecting device is used for projecting these characters onto photographic material wetted developer. It is already known to use photographic material having a steep gradation and a generally low sensitivity (German Auslegeschrift No. 1,145,490), however, this method was not generally adopted though it can be carried out in daylight conditions.
More in use are devices utilized in dark rooms wherein in operation of photographic lettering is carried out under red light, while the exposure of the photomaterial is effected with white light.
Photographic printing apparatus to be used under daylight conditions are also known which have light-tight regions wherein the photomaterial and the exposed character are included. An example thereof is U.S. Pat. No. 2,883,918 to W. P. Mosteller showing a sheet of opaque material having photosensitive material secured to undersurface thereof and being in contact with negative printing character sheet which can be exposed by light which is projected upwardly through an opening in the table top. In order to make visible what is printed, a character index sheet which is coupled to the negative printing character sheet and a layout sheet coupled to the photomaterial are provided to be moved relatively to one another and in synchronism to the sheet to which they are coupled. A further projecting device is for illuminating a spot which corresponds to the exposed spot though that a corresponding positive letter is illuminated which just can be produced by the apparatus on the photomaterial. This known photographic lettering device is expensive and the operation is complicated.
It is an object of the invention to provide an apparatus for photographically producing characters which is simple in its design.
A further object of the invention is to create an apparatus for photographically producing characters which can easily be operated.
In accordance with the invention, the apparatus for photographically producing characters or other representations comprises a light box for supporting photomaterial and other sheets and illuminating same with non-actinic light, a record carrier film having transparent regions in the form of the characters and an opaque background to shortwave light, and a flash device for producing shortwave light on those spots where the characters are to be produced. Since the characters or other representation appear immediately after exposure by shortwave light, the characters can be produced in context and without interruption by developing steps being carried out separately.
The photomaterial needed which is insensitive to daylight and sensitive to shortwave light is available to low costs and has to be wetted by developer liquid and covered with a protecting sheet. It is also possible to prepare such covered and protected photomaterial to be sold for the purposes of invention.
The light box has a light source for non-nactinic light, that is to say which does not blacken the photomaterial. Light in the visible region is such non-actinic light. Preferably yellow light is used which has a good contrast to the red or sepia coloured background of the record carrier film yet having a component which penetrates through that background.
The record carrier film preferably is a negative film which is transparent for the characters or other representations, whereas the background is distinctive to the characters and opaque for shortwave light.
The flash device has the usual tubular discharge lamp which will produce shortwave light. An aperture is provided to narrow the light flow onto a spot corresponding to size of a character or other representation to be produced.
In order to facilitate positioning of the record carrier film, a grid can be used wherein the characters already produced and the respective character to be produced appear. The light source of the light box will illuminate this grid which is visible through transparent sheets on the light box.